Crossover Design Planner
Overview
The Crossover Design Planner helps you design crossover trials where each subject receives multiple treatments in sequence. Generate balanced Latin Square and Williams Square designs that control for period effects and carryover effects. Calculate washout periods, verify balance, and export sequence allocations for implementation in clinical trials and repeated measures studies.
Tips
- Crossover designs are powerful because each subject serves as their own control, increasing precision
- Always include an adequate washout period between treatments to avoid carryover effects
- Williams Square designs are preferred when you’re concerned about first-order carryover effects
- Latin Square ensures each treatment appears in each period exactly once across subjects
- Use at least n subjects per sequence where n is the number of treatments for good balance
- Counterbalancing ensures that order effects don’t confound treatment effects
- Subjects who drop out can cause imbalance - plan for 10-15% more subjects than needed
- Not suitable if treatment has permanent effects (e.g., surgery, cure)
- Crossover designs work best for chronic stable conditions, not acute illnesses
- Document your washout period justification based on pharmacokinetics or biological plausibility